Television method and apparatus



TELEVISION METHOD AND APPARATUS Filed June 26, 1951 Patented Mar. 2,1937 irso sTATEs PATENT OFFICE TELEVISION METHOD AND APPARATUSApplication June 26, 1931, Serial No. 546,984

21 Claims.

This invention relates to television methods and apparatus.

Present day apparatus for translating a scene or a picture intoelectrical pulsations of such character that, after transmission of suchimpulses, either by wire, or by the radiated electromagnetic waves ofwireless or the so-called wired wireless methods of transmission, tosome point removed from the neighborhood of such scene or picture, thereto be retranslated into light gradations to reproduce the appearance ofthe picture or scene, requires the use of some mechanical moving part,such as a scanning disk, well known to the experimenter in this field.The synchronization of a disk for this purpose at the transmittingstation, with a similar disk at the receiving station, the accuracy andidentity necessary in the relation of number of apertures, their size,their exact arrangement on the disk, and similar details of constructionof both disks, the great number of holes necessary in order to produce aseemly picture or image of any real value, the fact that the picture orscene as reproduced by the rotating disk has a curvedline, as againstthe desired straight-line, appearance, and many other like features,have been the problems with which the experimenters have contended intheir efforts to make practical the transmission to and propervisualization at, a

distance removed from their location, of scenes,

or the like.

Furthermore, the light medium showing the necessary reactivity withrelation to variation in signal strength that is practical in instantlytranslating such variations in signal strength into sharp variations oflighting for such oper ations has been the neon bulb, the lighting valueof which is very low, the color of the light given oil by such bulb alsonot being very agreeable when an image is constantly to be viewed insuch light.

Furthermore, the customary rapidly rotating scanning disk requiresaccurate control of motor speed at both transmitting and receivingstations for proper synchronization during the production of televisionpictures. Even where synchronous motors are used, if there be but aslight difference between the frequencies at the two stations, thescanning disks are thrown out of synchronization and the image, which,after considerable labor, has been brought to visibility, will bedistorted.

It is an object of the invention tov provide a television system inwhich mechanical scansion is eliminated. In this method of television,ad-

vantage is taken of the effect upon light rays, and especially uponpolarized light, of magnetic fields of varying intensity.

It is also an object of the invention to provide a system of televisionin which variations of the 5 light intensity of the light source asdependent upon the intensity of the received signal is not a "part-01the scanning system of the receiving unit; in the essential operationfollowed in the practice of this invention, the light source itself 10produces a constant illumination during the operation of the scanningmeans. The receiving system is of such character that light rays,derived from a light source of any color characteristic, and especiallythose sources generally 15 characterized as emitting white light, suchas the electric arc, the customarily used incandescent filament bulb, orsimilar illuminating element, may be used so that an image in thecustomary variations of white and black may 20 be produced.

It is a further object of the invention to provide a television systemin which variations of magnetic fields, used in scanning elements at thereceiving station, may be accurately synchro- 25 nized with similarscanning elements at the transmitting station. In carrying out certainfeatures of the invention, polarized light is passed to an analyzer setto blot out all light passing normally thereto. By means of properlycon- 30 trolled magnetic fields, the polarized light rays are afiectedat particular points transversely of their extent so that, at suchpoints, the rays will be out of phase with the analyzer and will passtherethrough, whereupon such rays, properly lo- 35 cated with referenceto the pattern of a screen, may, in the transmitting system where thelight rays have passed through the scanning magnetic fields in varyingintensities, be used to affect, in varying degrees, a light sensitivecell for con- 4 verting such light variations into a similarly varyingelectric current for modulating a transmitting circuit, or, in thereceiving system, rays of polarized light be varied in intensity inproportion to the intensity of the signal received 5 from a transmittingsystem of the above type;

It is to be understood that this system may also be applied in suchcases where the analyzer is set to be entirely, or to some predetermineddegree, in phase with the normal polarized light, 50 while the rotatingfields will be active to rotate the light toward an out-of-phaserelation to the analyzer.

It is necessary that the light pulsations produced at the transmttingand the receiving sta- 55 tions should not only be synchronized but eachpulsation at the transmitting station, resulting from light intensity ata particular location upon a screen at that station, should result in aneX- actly timed light effect at the receiving station of substantiallythe same, or proportionately the same, light strength as that of thelight rays from which the pulsation arose, this light effect beinglocated upon the receiving screen in identically the same position asthat from which the pulsation arose. For this purpose, as a part of thisinvention, the scanning circuits and their currents are arranged forinstantaneous synchronization, without the use of mechanical means, sothat the pulsations of light at the receiving station will be controlledentirely by the current of the transmitting station without thenecessity of mechanically synchronizing the two stations, as is nownecessary in the cases of mechanical transmission and reception.

Other objects of this invention will be hereinafter set forth, or willbe apparent from the description and the drawing, in which are illustrated a number of embodiments of apparatus for carrying out theinvention.

The invention, however, is not intended to be restricted to theparticular constructions and arrangement of parts of such apparatus, norto the particular applications of such apparatus, herein shown anddescribed, nor to the specific methods of operation, nor to the variousdetails thereof, as the same may be modified in various particulars orbe applied in many varied relations without departing from the spiritand scope of the invention, some practical embodiments being hereinillustrated and described without attempting to show all the variousforms and modifications in which the invention might be embodied.

For the attainment of these objects and of such other objects as mayhereinafter appear or be pointed out, I have illustrated an embodimentof my invention in the drawing wherein:-

Fig. 1 is a diagrammatic layout of a television transmitting systemembodying the invention;

Fig. 2 is a similar view of a receiving system embodying the invention;

Fig. 3 is a layout for a scanning element of the type used in thesystems shown in Figs. 1 and 2; and

Figs. 4, 5, 6, and 7 are detailed elevational views, partly in section,of coils used for the scanning element.

Light rays, when transmitted through many types of media, one of whichis the well known Nicol prism, become polarized, that is, the light raysbecome imbued with certain properties which distinguish them fromordinary light rays. For instance, if such polarized light be directedthrough a Nicol prism which has had the common plane of the unitedprisms turned from the position of the original polarizing prism, thepolarized light rays will be incapable of transmission. However, if theprism, so arranged, is now rotated on its axis, some light will passthrough, the amount increasing until a maximum will be reached, afterwhich the amount of light passed will decrease.

It has been found that the same effect of passage of the light raysthrough the so-called analyzer is produced, without actual physicalrotation of the analyzer prism, by the action of magnetic fields uponthe light rays which are rotated with relation to the analyzer prism soas to permit their passage. Furthermore, the intensity or quantity ofthe light passed varies as the degree of rotation, and, therefore, withthe intensity of the magnetic field; the intensity of the latter may, ofcourse, be made a factor of the strength of an electric current passingthrough a solenoid or similar magnetic-field-producing element whichdepends for its magnetic strength upon an electric current flowingthrough a circuit.

For the purpose of this invention, these principles are embodied into asystem of scanning a scene, or similar light ray emitting element, andfor translating the varying current thus produced back into a scene orpicture similar to the original. On the drawing, the scene isrepresented at ill, which, in this case, is intended to be the face of aclock, or similar circular object. The particular purpose for which thedisclosed apparatus is designed is to transmit the light effectsproduced as the hands of a clock rotate. For this purpose, light raysradiating from the clock face are converged by a condensing lens l2through a paralleling lens I2a, thence through a Nicol prism l4, allwithin a housing I which here is represented entirely diagrammatically.These light rays, in their polarized condition, are now affected by adiverging lens I8 and a paralleling lens ISA so that their effect willbe spread over substantially the entire effective surface of thescanning element 20 through which they now pass. The specificconstruction of the scanning element, embodying the invention inpreferred form, will be described more fully hereinafter.

The light rays, after they have been acted upon by the scanning element,pass to and through a lens 22 by which they are condensed and focusedupon an analyzer 23 of any preferred construction, from which the lightrays which are not blotted out thereby are transmitted to affect thelight sensitive element of a light sensitive cell 25. The variations ofelectrical conditions in this cell may be used to modulate the outputcircuit of a transmitter 26, the construction of which may follow anydesired or well known form, or such variations may be used to produce avarying current in a conductor. If the variations are to be transmittedby a transmitter 28, the modulated wave may be radiated in any desiredmanner, as, for instance, between an antenna and ground circuit 28. Thelenses I2, in, 53, 58a, and 22 are merely the diagrammaticrepresentation of the necessary optical systems for bringing the lightrays into the desired relationships to the elements of the transmittingsystem.

The scanning element 28 preferably consists of a plate of somerefractive material, such as glass, quartz, or similar lighttransmitting substance, to one face 35 of which are secured a pluralityof coils 32, the axes of which, in a preferred construction, areparallel to each other and. also to the mean direction of light rayspassing from scene 5!] through lens l2. As appears in Fig. 3, thesecoils, in one desired arrangement, are arranged on face 3% in concentriocircles and are wired in series so that an electric charge, entering thefirst circle 3G, will first pass through all coils in that circle, andthen pass on to the coils in the next succeeding circle 35, and so onout to the outer extremity of the element 20.

As appears from Figs. 4 to '7, inclusive, the axes of these coils areperpendicular to the plate, and, therefore, their fields, as the chargepasses through them, will be most intense within their extent and alongtheir axes. Their light rotating effect would, therefore, be a maximumwithin such coils.

As light, which has passed through lenses 12 and l2a, the prism l4 andthe lenses l8 and 18a, arrives at and moves past coils 32, the electromagnetic effect produced by these coils will produce rotation of theplane of the polarized light, the degree of rotation depending upon theintensity of the magnetic fields, and, therefore, of the current flow in'a particular coil.

The particular manner in which the scanning element is made effective isnot specifically important. It is merely necessary to arrange the coils32 and have them connected to a power source or power sources so thateach of the coils at one station will become energized :at a distincttime, this energization of a particular coil being simultaneous withthat of 'a coil, identically located with respect to its screen, at theother station. The energization of each coil preferably is distinctfro-m that of the others. To accomplish this, it may be desirable toenergize each coil from an individual power source, timed with relationto the others to energize :its particular coil at a desired instant. Forinstance, this may be done by providing each coil with a vacuum tuberelay, discharging through the coil at predetermined intervals.

However, in the preferred arrangement, the coils are connected inseries, as indicated above. The movement of an electric charge,originating at some source and then passing from that source, throughthe series connected coils, back to the source, produces what isotherwise known as an electric current, and consumes a definite timeinterval for its passage. By guiding an electric current through coils'32 in the predetermined order, each of the coils, during the passage ofthe electric current, becomes energized and a magnetic field is createdimmediately around it. These magnetic fields, as has previously beendiscussed, rotate polarized light passing through the particular coilsubstantially parallel to its axis. This energization is, however, madealmost instantaneous, the charge passing on from coil to coil, andinstantaneously energizing each one of them in rapid succession.Preferably some means, such as damping coils or the like, may beinterposed, in such an arrangement, between successive coils, in orderthat the electric charge may be delayed in passing from coil to the nextone so that but one coil at a time will be afiected by the charge at anyone instant. Such areas of face 30 of the plate 28 as are disposed otherthan at the coils may be blanked by positioning thereon :some means,such as paint, for blotting out light.

The result is the rotation of polarized light at a number of differentneighborhoods, so that a number of spots of light will be transmitted inaccordance with the instantaneous position of the moving charge ofscanning current. Of course, if the image itself is dark, no light wouldhave originated from it in the first place, and, therefore, the scanningelement would affect no light. But, if light were transmitted from lightportions of the scene, this light would be transmitted to the light cell24 by the element and the subsequent analyzer as a large number ofdistinct light impulses of strengths, varying in accordance with whetherthe portion of the scanning element, at the instant a particular coilwas active, was illuminated by such polarized light.

The current flow through the coils may be produced by a plurality ofcharges, discharged through the coils in a predeterminedly timedrelationship so that the current will have a pulsating character, as,for instance, that produced by an alternating current, or by aninterrupted direct current. The coils 32 will thus become magneticallyactive in a predetermined consecutive relationship, but, due to the factthat the charges will move from coil to coil there will be magneticactivity only at a predetermined point or area in the extent of theplate, at any particular time. In other words, at any specific instant,light rays will be affected by the magnetic fields only at a certaindistinct point or area of very small extent so that only such rays willbe rotated sufiiciently that the analyzer prism '23 would not bar themfrom passage thereby.

It is to be'realized, of course, that the intensity of light-atdifferent areas of the plate would vary in accordance with the lighttransmitted from scene H]. In other words, where the effective coil hasno light transmitted thereto, it, of course, will rotate no light, and adark spot, and no resultant signal from the light sensitive cell, willresult; as the intensity of the light passing by the active coilincreases, for the same strength of magnetic field, rotation passes morelight and there results a greater signal from the cell. In this manner,the impulses created in cell 24 would be varied in accordance with theintensity of the light rays at particular areas or points in scene I'D,as visualized at element 20. These light sensations would thusbeconverted into a series of electrical impulses of varying strengths,such that, with apparatus shown in Figure 2, or embodying principlessimilar thereto, they might be converted again into a visible sceneexactly that of the one depicted at the element 20.

In conjunction with receiving apparatus 45], there maybe used any lightsource, such as an electric are 42, or similar'light producing element.Since the operation of the light source is not a material item inconnection with the features of this apparatus, that is, the variationin illuminaton and other features of the scanning system do not relyupon any time period or other activity of such source, the source maytake any form desirable with relation to the particular work to be done.

Light from the source is passed through a paralleling lens 42A thencethrough a polarizing meanssuch as prism 44, thereafter being diverged bya lens 46, thence through a paralleling lens 46A, so as to coversubstantially the entire effective extent of a scanning element 48,similar in construction to element 2! Light, after having passed element48, is condensed bythe lens 50 and focused to pass through a parallelinglens 50A,'thence through an analyzer 52. Such light as had been rotatedby the magnetic fields at element 48 will pass through the analyzer; allother light will be blotted out.

Light passing analyzer s2 is directed through some refractive substance,preferably in the form of a prism or cylinder 55, the material used, ina preferred arrangement, being glass or similar highly refractivesubstance which cooperates with magnetic fields to effect rotation ofpolarized light. Wound on the cylinder or'prism is a coil 56, which isconnected to the output receiver circult B of 'a receiving tuner 68,energized and controlled by the converted wave from the antenna- .groundcircuit 62. This circuit and the receiving tuner are intended to convertthe impulses from a transmitter-such as that shown in Figure l, and toamplify such electrical impulses so that the resultant current may bepassed through coil 56 to eiiect rotation of such polarized light as ispassed through analyzer 52 in a degree varying with the intensity of thevarying received signal.

Beyond cylinder 54 is positioned another prism (it, intended to operateas an analyzer for light rays passed by analyzer 52. Normally,therefore, prism 6 3 would act to blot out all light passed by theanalyzer. However, such of the light which would be additionally rotatedby the effect of the current in coil 55 would pass prism 6 and then bediverged by a lens 66 so that the image therefrom may be viewed directlyby the eye of an observer, or be projected upon a screen 68.

In order to assure proper synchronization of movement of the chargesthrough the circuits of the respective scanning elements 20 and 48, atransmitter 'EJ may be used in conjunction with transmitter 28.Transmitter 7!], in such case, is modulated by the surge of the chargesconstituting the current flow through the coils or elements 20. Thismodulated wave is then radiated, or otherwise transmitted, to affect thereceiving tuner 72 located in conjunction with the receiving tuner 60 atthe receiving station. Tuner 12 in turn may control amplificationapparatus whereby a current, exactly similar in its properties to thatpassing through scanning element 29 and of sufiicient strength to aiTectpolarized light, will be passed through scanning element 48. In otherwords, the passage of light at similarly located coils of the twoelements 20 and 48 will be positively synchronized without anymechanical requirement of pulling into phase, the light impulses passedfrom the polarizers and by the first analyzers in each case beingexactly synchronized and identically arranged in the screen pattern ofthe scanning elements.

At the receiving apparatus, the scanning element merely produces anumber of similar impulses of polarized light for each energization ofone of the coils. These impulses are similar in number to those whichwould have been produced by the scanning element 20 if the scene It!were completely light. The control of prism 64 and its coil 58, however,results in blotting out, or passing by, or grading, these light impulsesin accordance with electrical impulses from cell 24. Since the twoelements 20 and 48 are exactly synchronized, the impulses from cell 24will vary .ie impulses from element 48 so that the appearance on screen68 will be graded in light and dark, substantially as was scene ID fromwhich the original impulses came.

The production of light and dark points will, in the transmittingapparatus, be controlled by the object or scene itself; in the receivingapparatus, by receiving tuner 60, its output circuit coil 55 and prism64. Since the light and dark effects produced by prism 64 and its coilare controlled by its associated circuit which, in turn, is under thedirect control of the varying current produced by the light and darkpoints of the object or scene, the light and dark points on screen 58will correspond exactly to those of the object; since the shutter effectof the scanning ele ments will be exactly in tune, the image on screendue to the persistence of vision, will correspond exactly to that of theobject or scene it).

Each of the scanning elements is preferably of exactly the sameconstruction, the coils 32 of each being arranged in similar concentriccircles, the coils and each of the respective circuits being of suchcharacteristics that electric charges passed through each will have thesame time period of movement for a complete cycle. The coils may beconnected in any particular sequence; in one embodiment, a currentimpulse, originating at one circle, will first pass through the coils inthat circle before proceeding to the coils in the next concentriccircle. However, this arrangement is not an absolute requisite as thecurrent may pass from any one coil to any other coil in a preferredorder. It is, however, desired that a substantially uniform effect oflines or circles be produced so that the resultant persistence of visionupon which all such arrangements are based will be of the least damagingeff-ect'to the vision of the person observing the phenomenon.

The coils 32 themselves may be built up in any particular manner. Inthis case, four constructions have been illustrated, the one in Fig. 4being merely that of a solenoid with an air core. Each coil is mountedupon a plate 74 of a highly refractive substance, and is disposed sothat the light rays from the lens H3 or the lens 66, as the case may be,will be parallel to the axis of the coil.

In Fig. 5, the coil is shown to have been wound within a metalliccylinder H5, preferably of some magnetic metal such as iron, it havingbeen found that the rotational efiect upon the light is greatly enhancedby the introduction of such magnetic metal. In Fig. 6, the coil is woundupon a cylinder 78 which is preferably a magnetic metal. Thisconstruction operates to effect even greater rotation of the lightbecause of the extreme concentration of the magnetic field resultingfrom the association of the coil and cylinder 18.

The construction of Fig. 7 is a preferred one. In this case, a portionof refractive material 88 is formed with a skin 82 of metal, such asiron, and upon the skin is wound coil 84 through which the scanningcurrent passes. In this case, the combination of the highly magneticfield and the highly refractive material result in extreme rotations oflight rays for relatively small currents passed through the coils.

Many other changes could be effected in the particular apparatusdesigned, and in the methods of operation set forth, and in the specificdetails thereof, without substantially departing from the inventionhereof which is intended to be defined in the accompanying claims, thespecific description hereinabove relating merely to some operativeembodiments for carrying out the spirit of the invention.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent is- 1. Scanning apparatusfor the purpose of reproducing an image of a scene at points removedfrom the locality of the scene, which includes: means for polarizinglight rays emanating from a source or scene, and a plurality ofindividually and periodically active magnetic field producing means forbreaking up the polarized light rays into a plurality of consecutivelyvisible light sensations, each of which has the intensity of a distinctportion of the source or scene.

2. Scanning apparatus for the purpose of reproducing an image of a sceneat points removed from the locality of the scene, which includes: meansfor polarizing light rays emanating from a source or scene, analyzermeans cooperating with the polarizing means, and a plurality ofindividually and periodically active magnetic field producing means tochange the phase relationship of the light rays between the polarizingand analyzing means for breaking up the polarized light rays into aplurality of consecutively visible light sensations, each of which hasthe intensity of and the same relative position as a distinct portion ofthe source or scene.

3. Scanning apparatus for the purpose of reproducing an image of a sceneat points removed from the locality of the scene, which includes: meansfor polarizing light rays emanating from a source or scene, a pluralityof coils to produce magnetic fields, and means for energizing the coilsin a predetermined consecutive relation for breaking up the polarizedlight rays into a plurality of consecutively visible light sensations,each of which has the intensity of a distinct portion of the source orscene.

4. Scanning apparatus for the purpose of reproducing an image. of ascene at points removed from the locality of the scene, which includes:means for polarizing light rays emanating from a source or scene, aplurality of coils to produce magnetic fields, and means for energizingthe coils periodically in a predetermined consecutive relation forbreaking up the polarized light rays into a plurality of consecutivelyvisible light sensations, each of which has the intensity of a distinctportion of the source or scene.

5. Scanning apparatus for the purpose of reproducing an image of a sceneat points removed from the locality of the scene, which includes: meansfor polarizing light rays emanating from a source or scene, analyzermeans cooperating with the polarizing means, a plurality of magneticfield producing means to change the phase relationship of the light raysbetween the polarizing and analyzing means, and means for energizing thecoils periodically in a predetermined consecutive relation for breakingup the polarized light rays into a plurality of consecutively visiblelight sensations, each of which has the intensity of and the samerelative position as a distinct portion of the source or scene. I

6. Scanning apparatus for the purpose of reproducing an image of a sceneat points removed from the locality of the scene, which includes: meansfor polarizing light rays emanating from a source or scene, a pluralityof series connected coils to produce magnetic fields, and means forenergizing the coils so that they are magnetically active individually,periodically and in a predetermined consecutive relation for breaking upthe polarized light rays into a plurality of consecutively visible lightsensations, each of which has the intensity of a distinct portion of thesource or scene.

'7. Scanning apparatus for the purpose of re producing an image of ascene at points removed from the locality of the scene, which includes:means for polarizing light rays emanating from a source or scene, and aplurality of magnetic field producing means for breaking up thepolarized light rays into a plurality of consecutively visible lightsensations, each of which has the intensity of a distinct portion of thesource or scene.

8. Scanning apparatus for the purpose of reproducing an image of a sceneat points-removed from the locality of the scene, which includes: meansfor polarizing light rays emanating from a source or scene, and aplurality of individually and periodically active magnetic fieldproducing means for breaking up the polarized light rays into aplurality of consecutively visible light sensations, each of which hasthe intensity of a distinct portion oiv the source or scene.

9. Scanning apparatus for the purpose of reproducing an image of a sceneat points removed from. the locality of the scene, which includes: meansfor polarizing light rays emanating from a source or scene, analyzermeans cooperating with the. polarizing means, and a plurality ofindividually and periodically active magnetic field producing means tochange the phase relationship of the light. rays between the polarizingand analyzing means for breaking up the polarized light. rays into aplurality of consecutively visible light. sensations, each of which hasthe intensity of a distinct portion of the source or scene.

10. Scanning apparatus for the purpose of reproducing an. image of ascene at points removed from the locality of the scene, which includes:means for polarizing lightrays emanating from a source or scene, and aplurality of series connected coils to produce magnetic fields forbreaking up the polarized light rays into a plurality of consecutivelyvisible light sensations, each of which has the intensity of a distinctportion of the source or scene.

11. Scanning apparatus for the purpose of reproducing an image of ascene at points removed from the locality of the scene, which includes:means for polarizing light rays emanating from a source or scene, aplurality of coils to produce magnetic fields, and means for energizingthe coils periodically in a predetermined consecutive relation forbreaking up the polarized light rays into a plurality of consecutivelyvisible light sensations, each of which has the intensity of a distinctportion of the source or scene.

12. Scanning apparatus for the purpose of reproducing an image of ascene at points removed irom the locality of the scene, which includes:means for polarizing light rays emanating from a source or scene,analyzer means cooperating with the polarizing means, a plurality ofcoils to produce magnetic fields to change the phase relationship of thelight rays between the polarizing and analyzing means, and means forenergizing the coils periodically in a predetermined consecutiverelation for breaking up the polarized light rays into a plurality ofconsecutively visible light sensations, each of which has the intensityof and the same relative position as a distinct portion of the source orscene.

13. Scanning apparatus for the purpose of reproducing an image of ascene at points removed from the locality of the scene, which includes:means for polarizing light rays emanating from a source or scene, aplurality of series connected coils to produce magnetic fields, andmeans for energizing the coils so that they are magnetically activeperiodically in a predetermined consecutive relation for breaking up thepolarized light rays into a plurality of consecutively visible lightsensations, each of which has the intensity of a distinct portion of thesource or scene.

14. Scanning apparatus for the purpose of reproducing an image of ascene at points removed from the locality of the scene, which includes:means for polarizing light rays emanating from a source or scene, aplurality of series consecutively visible light sensations, each ofwhich has the intensity of a distinct portion of the source or scene.

15. The method of television which consists at the transmitting stationin breaking up the light, emitted from a scene to be transmitted, into aplurality of contemporaneously existent beams normally inoperative forpurposes of transmission to the receiving station, causing an electricimpulse to act on said beams successively and thereby render them singlyand successively operative for transmission, whereby a single electricimpulse will cause a scanning of the entire scenic effect, the speed ofscanning being dependent on the speed of transmission of an electricimpulse through the path provided for it, and transmitting said impulseto the receiving station; and which consists at the receiving station inbreaking up the image-forming light rays into a plurality ofcontemporaneously existent beams similar in number and position to thebeams at the transmitting end, and normally inoperative, and subjectingsaid beams successively and in the same sequence to the electric impulsereceived from the transmitting station, whereby said beams are renderedsuccessively effective for a point by point image construction.

16. The method of television which consists at the transmitting stationin breaking up the light, emitted from a scene to be transmitted, into aplurality of contemporaneously existent beams normally inoperative forpurposes of transmission to the receiving station, causing an electricimpulse to act on said beams successively and thereby render them singlyand successively operative for transmission, whereby a single electricimpulse will cause a scanning of the entire scenic effect, the speed ofscanning being dependent on the speed of transmission of an electricimpulse through the path provided for it and transmitting said impulseto the receiving station; and which consists at the receiving station inbreaking up the image-forming light rays into a plurality ofcontemporaneously existent beams similar in number and position to thebeams at the transmitting end, and normally inoperative, and subjectingsaid beams successively and in the same sequence to the electric impulsereceived from the transmitting station, whereby said beams are renderedsuccessively effective for a point by point image construction and meansfor transmitting the operative beams from the transmitting sta tion intoelectric energy for controlling the intensity of the corresponding beamsat the receiving station.

17. In a television system in which the light emitted by a scenic effectto be transmitted is plane polarized, broken up into a plurality oflight beams and subjected to an analyzer adjusted to intercept saidpolarized beams, a plurality of means, one of which is associated witheach beam and adapted, when operative, to affect it so as to! counteractthe intercepting action of said analyzer, said means being electricallyassociated in such a manner that on passing an electric impulsetherethrough they will become successively operative in a predeterminedsequence, to counteract the intercepting effect of the analyzer on thesuccessive beams, and thereby scan the scenic effect for purposes oftransmission, and whereby said scanning of the entire scenic effecttakes place in the time required for the passage of a single electricimpulse through the system of electrically associated means.

18. In a television system in which the light emitted by a scenic effectto be transmitted is plane polarized, broken up into a plurality oflight beams and subjected to an analyzer adjusted to intercept saidpolarized beams, a plurality of means, one of which is associated witheach beam and adapted, when operative, to eiiect it so as to counteractthe intercepting action of said analyzer, said means being electricallyassociated in such a manner that on passing an electric impulsetherethrough they will become successively operative in a predeterminedsequence, to counteract the intercepting eifect of the analyzer on thesuccessive beams, and thereby scan the scenic effect for purposes oftransmission, and whereby said scanning of the entire scenic effecttakes place in the time required for the passage of a single electricimpulse through the system of electrically associated means, andelectric impulse retarding means interposed between each pair of saidfirstmentioned means, whereby said electric impulse will render only oneof said first-mentioned means operative at a time.

19. In a television system, means for plane polarizing the field oflight rays proceeding from the object; magneto-optic scanning meansadapted to receive and transmit the said field of polarized rays and tobreak it up into small portions, and to transmit said portions insuccession, one at a time, until the entire field is covered, saidscanning means comprising a plurality of electromagnet coils eachpositioned with its magnetic axis substantially coinciding with thedirection of the polarized light flux, and each having positionedrelatively to each coil and in the path of said polarized rays and sothat it will be aifected by the magnetic field of the coil, a lighttransmitting substance that will be rendered birefringent by the actionof the magnetic field thereon, and thereby change the plane of saidplane polarized rays, and analyzing means positioned in the path of therays transmitted through said light transmitting substance and adaptedto transmit only those rays that have been affected by the said magneticfields of said coils, said co-ils being connected in a series, and meansto pass successive electric impulses through said coils, so timed thatany given impulse will have completely passed through all the coilsbefore the succeeding impulse enters the first coil; a light sensitivemeans adapted to receive said scanned rays and to translate them intoelectric impulses varying in magnitude according to the intensity of thelight received thereby, and means for transmitting said varying electricimpulses to a receiving station.

20. In a television system, means for producing a field of light rays,means for plane polarizing said field of light rays; magneto-opticscanning means for breaking up said field of light rays into smallportions and to transmit said portions in succession, one at a time,until the entire field is covered, said scanning means comprising aplurality of electromagnet coils each positioned with its magnetic axissubstantially coinciding with the direction of the polarized light flux,and each having positioned relatively to each coil and in the path ofsaid polarized rays and so that it will be affected by the magneticfield of the coil, a light transmitting substance that will be renderedbirefringent by the action of the magnetic field thereon, and therebychange the plane of said plane polarized rays, and analyzing meanspositioned in the path of the rays transmitted through saidlight-transmitting substance and adapted to transmit only those raysthat have been affected by the said magnetic fields of said coils, saidcoils being connected in series, and means to pass successive electricimpulses through said coils, so timed that any given impulse will havecompletely passed through all the coils before the succeeding impulseenters the first coil, and means for controlling the intensity of eachtransmitted small portion of said field of light rays in accordance withone of the aforesaid electrical impulses, the action of each of saidimpulses being timed to correspond with the transmission of one of saidtransmitted small portions of the field of light rays, and means forfocussing each of said transmitted portions on a screen.

21. A method of transmitting electrical impulses created by varyinglight efiects of an object, into an image having characteristics of theobject from which the light rays producing the effects originated, whichcomprises: producing a flow of light, plane polarizing said light,twisting the plane of polarization of fractional portions of said fiowof light periodically at each point by the magneto-optical action of aperiodically varying magnetic field, and timing said twisting of eachfractional portion consecutively for the various points of the field,thereafter transmitting only those rays that have had their plane ofpolarization twisted, and magnetically varying the intensity thereof inaccordance with the pulsations of the said electrical impulses createdby the aforesaid varying light effects of the object.

CHARLES A. BIRCH-FIELD.

